In recent years, fuel cell vehicles, which generate power using hydrogen and oxygen as fuel and travel by driving a motor using this power, have been widely developed. The fuel cell is excellent in terms of an environment aspect, and may realize high energy efficiency such that the fuel cell is very promising as an energy source for vehicles in the future.
Commonly, the fuel cell that is mounted on the vehicle includes a plurality of cells and the respective cells are connected in series to generate a high voltage, for example, 200 V. This voltage is supplied to a motor to drive the vehicle.
This fuel cell vehicle is provided with a voltage detection device that measures the voltage that is generated in each cell. Whether or not an appropriate voltage is generated is monitored by classifying a plurality of cells into blocks, and by measuring a cell voltage for each block (for example, refer to Patent Literature 1). For example, in a fuel cell including 55 cells in total, 11 cells are set to one block, and in total, five blocks are configured. The cell voltage for each block is measured by a voltage detecting IC that is provided for each block, and it is monitored whether or not the cell voltage is maintained at a normal voltage.
At this time, as is the case with the above-described example, in a case where 55 cells in total are classified into five blocks, each block having 11 cells, a voltage that is output from one block is substantially 40 V, and the voltage detecting IC, which is provided in each block, operates using a voltage of substantially 40 V output from each cell as a power source voltage to measure a voltage for each block. That is, the voltage detecting IC operates using a cell voltage that is an object to be measured as a power source voltage.
Here, in a case where fuel is not supplied to a cell provided in the fuel cell, since a voltage is not generated in the cell of each block, the voltage for the power source is not supplied to the voltage detecting IC, and thus the voltage detecting IC does not operate.